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Antibacterial hydrogels are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected-wound healing. The abuse of antibiotics leads to drug resistance. Recent developments have demonstrated that the delivery of inorganic bactericidal agents in hydrogels can drive the wound healing process; however, this approach is complicated by external light stimuli, cytotoxicity, nondegradability, and sophisticated fabrication. Herein, an inherent antibacterial, bioresorbable hydrogel was developed by the spontaneous self-aggregation of amphiphilic, oxadiazole-group-decorated quaternary ammonium salts (QAS)-conjugated poly(e-caprolactone)-poly(ethylene glycol)-poly(e-caprolactone) (PCEC-QAS) micellar nanoantimicrobials for methicillin-resistant Staphylococcus aureus (MRSA)-infected cutaneous wound healing. The PCEC-QAS hydrogel showed a stable gel state within the temperature range of 5-50 °C and antibacterial efficacy against both Gram-negative and -positive bacteria in vitro and in vivo. Additionally, the PCEC-QAS hydrogel facilitated the cell spreading, proliferation, and migration without cytotoxicity. An in vivo degradation and skin defect healing study suggested the PCEC-QAS hydrogel was totally absorbed without local or systemic toxicity and could promote wound repair in the absence of drugs, cytokines, or cells. Significantly, this hydrogel accelerated the regeneration of a MRSA-infected full-thickness impaired skin wound by successfully reconstructing an intact and thick epidermis similar to normal mouse skin. Collectively, a self-assembling PCEC-QAS antibacterial hydrogel is a promising dressing material to promote skin regeneration and prevent bacterial infection without additional drugs, cells, light irradiation, or delivery systems, providing a simple but effective strategy for treating dermal wounds.

We study the evolution of accretion disk around a supermassive binary black hole with equal mass using non-relativistic hydrodynamical simulations performed with FARGO3D. Compared with previous studies with the Newtonian hydrodynamics, here, we adopt the post-Newtonian hydrodynamics using the near zone metric of the binary black hole. In contrast to the Newtonian investigation, we find that there is a dramatic difference in the post-Newtonian regime, gap formed by the circumbinary accretion disk around the binary with equal mass is wider with the post-Newtonian hydrodynamics than that with the Newtonian hydrodynamics and is independent of disk viscosity given that hydrodynamical simulations are run for about the same factor times the viscous timescale associated with different viscosities. This may present unique observable signatures of the continuum emission in such binary-disk system., 10 pages, 8 figures. Published in MNRAS

Poly(l-lactic acid) (PLLA) scaffolds have been used in regenerative medicine, however, they commonly suffer from low flexibility, restricting their application in the repair and reconstruction of soft tissues. In this study, poly(l-lactide-co-e-caprolactone) (PLCL) copolymers were examined to modulate the elasticity of PLLA with the random presence of CL units in PLLA. Thermodynamic analysis revealed that the introduction of PCL could significantly decrease the melting point and glass transition temperature of PLLA, benefiting the extrusion and printing of PLCL. Diverse scaffolds with designed architectures including porous cubes with or without large holes, cambered plates with holes and round tubes could be easily constructed by 3D printing. In the process of elastic deformation, the maximum elastic stress of the copolymer scaffold was obviously increased from 19.6 to 31.5 MPa when the relative content of PCL was increased to 70%, while the elongation at break was evidently increased from 388% to about 1974%. The Young's modulus of PLCL was also significantly decreased (P < 0.05) in comparison with that of PLLA. PLCL scaffolds have good platelet and endotheliocyte adhesion ability and no obvious hemolysis was observed. In vivo subcutaneous implantation of PLCL scaffolds demonstrated superior biocompatibility. Collectively, this work highlights that copolymerization of PCL segments into PLLA is an effective approach to tune the 3D printability and the stiffness and elasticity of PLLA scaffolds. PLCL scaffolds hold great promise for the regeneration of soft tissues including but not limited to cartilage, myocardium, muscle, tendon and nervous tissues.

BACKGROUND: Currently, nanobodies are undergoing intensive studies due to their characteristics of nanoscale size, high affinity and specificity, and deep tissue penetration. The development of novel and simplified methods to purify nanobodies is required because high purity and high recovery are the limiting factors for the downstream preparation of nanobodies. RESULTS: In this study, ammonium sulfate precipitation (ASP) and electropositive multimodal chromatography (Capto MMC) were integrated for tag‐free nanobody (2D5) purification. ASP was our first choice for protein purification because the process is simple, easy to operate, and has low cost. ASP achieved a 36% reduction in Escherichia coli host cell proteins (HCPs), a 99.1% reduction in E. coli host cell DNA, and an 85.1% reduction in endotoxins with a recovery of 81.7% and a purity enhancement from 6.2% to 73.9%. Capto MMC was seamlessly integrated for 2D5 purification. The recovery of this step was 83.0%. The entire two‐step purification platform yielded 2D5 with 397 ppm of HCPs, 198 ppb of DNA, 204 EU/mL of endotoxins, and total protein recovery of 67.8%. The purity of 2D5 was 97.5%. The purification method was also used to purify a nanobody against PD‐L1 (KPU) with 97.7% purity, > 95.7% recovery, 223 ppm of HCPs, 634 ppb of DNA and 154 EU/mL of endotoxins. CONCLUSION: The established method had no effect on the affinity of 2D5. A simple and efficient purification platform that integrates ASP and Capto MMC was established, providing a more promising alternative to the conventional affinity chromatography‐based nanobody purification strategy. © 2019 Society of Chemical Industry

The reflectance spectrum of plant leaves is mainly controlled by the loose porous structure in the near-infrared (NIR) region. Here, hollow polystyrene-polydivinylbenzene (PS-PDVB) microspheres can be designed into amorphous photonic crystals by various methods. The result of spectral tests showed that the reflectance spectra of the amorphous photonic crystals and plant leaves exhibited the similar characteristics in 0.76–1.30 μm bands. More importantly, the amorphous photonic crystals were coated with RefA1 protein on the surface to display stimuli-responsiveness under acid stimuli. We believe that the amorphous photonic crystals have a variety of promising applications in NIR camouflage materials.

The effect of gravitational wave of cosmological wavelength on the gravitational lensing is investigated. When the source, deflector, and observer are aligned in a highly symmetric configuration, an Einstein ring will be observed by the observer. There will be no time delays between different locations on the Einstein ring in the absence of gravitational wave. Otherwise, time delays between different locations on the Einstein ring will emerge if cosmological gravitational wave propagates through the system. Previous studies demonstrated that the time delay resulting from the aligned source-deflector-observer configuration in the presence of gravitational wave of cosmological wavelength could be equivalent to that of a similar lens with a nonaligned source-deflector-observer configuration in the absence of gravitational wave. Results in this work show that gravitational lens with the aligned source-deflector-observer configuration could serve as a potential gravitational wave detector when the whole Einstein ring observed by the observer is taken into account., Comment: 5 pages, 1 figure. Published in Physical Review D

Nerve growth factor (NGF) is an essential trophic factor for the growth and survival of neurons in the central and peripheral nervous systems. For many years, mouse NGF (mNGF) has been used to treat various neuronal and non-neuronal disorders. However, the biological activity of human NGF (hNGF) is significantly higher than that of mNGF in human cells. Using the CRISPR/Cas9 system, we constructed the transgenic mice expressing hNGF specifically in their submandibular glands. As demonstrated by fluorescence immunohistochemical staining, these mice produced hNGF successfully, with 0.8 mg produced per gram of submandibular glands. hNGF with 99% purity was successfully extracted by two-step ion-exchange chromatography and one-step size-exclusion chromatography from the submandibular glands of these transgenic mice. Further, the purified hNGF was verified by LC–MS/MS. We analyzed the NH2-terminus of hNGF using both Edman degradation and LC–MS/MS-based methods. Both results showed that the obtained hNGF lost the NH2-terminal octapeptide (SSSHPIFH). Moreover, the produced hNGF demonstrated a strong promotion in the proliferation of TF1 cells.

Acid precipitation has been demonstrated as a clarification method for cell culture supernatant (CCS) pretreatment during Immunoglobulin G (IgG) purification. In this study, the responses of IgG, non-histone host cell protein (n-hHCP), histone, and DNA to different pHs in the presence of salt (NaCl) at various concentrations were systematically studied. IgG loss was closely associated with the precipitation of chromatin heteroaggregates, in which DNA/histone showed significant decreases along with the acidification of buffer environment. In addition, DNA showed full recovery after pH neutralization, while the low pH treatment induced histone precipitation was permanent and could not be reverted upon pH increase. Analytical size exclusion chromatography (SEC) profiles further indicated the agglomeration and reduction of chromatin heteroaggregates along with lower pH. Protein A chromatography benefited from the reduction of chromatin heteroaggregates and showed significant enhancement of the removal of impurities as well as for IgG recovery. For the first time, this study correlated CCS acidification with chromatin heteroaggregate removal and illustrated its ramification for the subsequent purification process.

Advance chromatin extraction, based on a fatty acid/allantoin/solid phase system, has been reported to significantly improve the purification performance of protein A chromatography, cation exchange chromatography and electronegative mixed-mode chromatography to capture monoclonal antibodies (mAbs). In this study, the beneficial effects of advance chromatin extraction were evaluated using electropositive mixed-mode chromatography and were demonstrated to significantly enhance the dynamic binding capacity and removal efficiency of various impurities. Moreover, retention of immunoglobulin G (IgG) molecules on electropositive mixed-mode resins uniquely followed two phases, which decreased and then increased along with the increase in salt concentration. The eluted IgG was directly loaded and further polished by void-exclusion anion exchange chromatography without adjusting the sample. After these two chromatographic steps, non-histone host cell protein (nh-HCP) content in the end-product was reduced to

Incorporating the radiation reaction force into two-fluid plasma in curved space, we get a set of one-fluid general relativistic magnetohydrodynamics (GRMHD) equations with the Landau-Lifshitz radiation reaction force. We analyze the importance of the radiation reaction acting on plasma around an astrophysical compact object., 11 pages, 1 figure, ApJ, in press

By taking into account the radiation reaction force, we derive a set of one-fluid relativistic magnetohydrody-namics (RMHD) equations with the Landau-Lifshitz radiation reaction force based on a relativistic two-fluid plasma. These equations could be used to situations where spatiotemporal scales of plasma's motion are suffi-ciently large., 9 pages, accepted by ApJ

Bacterial cellulose (BC) is a natural product with multiple properties, which has been utilized in tissue engineering. However, cell adhesion and proliferation are reported to be weaker on native BC, providing less support compared to other types of biomaterials, like collagen. To increase the biocompatibility and the medical performance of BC, in situ modification is used to add carboxymethyl group to BC. By partially changing the structure and physical properties of BC, carboxymethylation significantly increases cell affinity and viability, especially on the initial cell adhesion. Furthermore, in the in vivo implantation, the tissue reaction shows that carboxymethylation significantly increases the biocompatibility of BC, exhibiting better tissue condition and a lower inflammatory reaction which are proved through HE staining and immunohistochemistry. The data prove that in situ carboxymethylation is a simple and direct way of improving the performance of BC in medical applications.

Nanobodies offer multiple advantages over conventional antibodies in terms of size, stability, solubility, immunogenicity, and production costs, with improved tumor uptake and blood clearance. Additionally, the recombinant expression of nanobodies is robust in various expression systems, such as Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris. P. pastoris is the most widely used microorganism for nanobody production, but all or almost all expression vectors developed for this system are based on the regulated promoter of the alcohol oxidase 1 gene (AOX1) that requires methanol for full induction. In this study, a constitutive anti-CEACAM5 nanobody expression system was constructed under the control of a glyceraldehyde-3-phosphate dehydrogenase promoter (GAP) promoter. The effects of different carbon sources and pH on nanobody expression were evaluated in shaking flask cultures. After 96 h of constitutive expression in shaking flask, a yield of 51.71 mg/L was obtained. In addition, this constitutive expression system produced nanobodies at equivalent yield and affinity to that produced by methanol-induced expression. The results of this study indicated that the use of a constitutive expression system is a promising alternative for the production of nanobodies applied for cancer diagnosis and therapy.

Non-protein A-based purification technology is increasingly needed in that protein A chromatography possesses mang inherent problems, such as the high material and operational costs, limited productivity, and leaching of the protein A ligand. In this study, antibody purification was first achieved by precipitation of the antibody from the cell culture supernatant (CCS) in a tubular reactor with a static mixer. The protein precipitates were efficiently intercepted by incorporating a depth filtration membrane directly after the mixer. Chromatin-directed cell culture clarification was shown to enable the full usage of the load of the filter membrane and also significantly reduced the burden of the subsequent purification step. The addition of NaCl to the CCS significantly increased the permeabilization of the filter membrane by increasing the loading capacity by up to 20%. The re-dissolved and eluted antibodies were further polished using single multimodal chromatography, which supported direct sample loading. The content of non-histone host cell protein (n-h-HCP) in the final product was less than 20 ppm, DNA was less than 1 ppb, and the aggregates was less than 0.05%. The overall antibody recovery was ˜82%. This method is a feasible alternative to the current protein A-dominant antibody purification platform and has high value and potential for widespread implementation.

Traditional purification platforms for monoclonal antibodies (mAbs) rely heavily on 3–4 step chromatographic operations with protein A affinity chromatography as the essential antibody capture approach. In this study, we applied for the first time the established fatty acid-mediated chromatin-directed clarification to cell fermentation broth. An efficient chromatin-directed cell culture fluid (CCF) clarification process was developed to remove most host DNA and histones, as well as reduce non-histone host cell proteins (n-h HCPs) by 94.7%, with a 92.5% IgG recovery yield. The pre-removal of a large amount of host cell contaminants allows tangential flow filtration (TFF) to concentrate clarified cell culture supernatant (CCS) and perform buffer exchange. High-capacity cation exchange chromatography (CEX) was shown to effectively remove the remaining host impurities. This new antibody purification platform achieves an 86.7% antibody recovery yield with an end-product meeting all clinical requirements, greatly shortening the antibody purification process and improving the antibody production efficiency.